SOMERVILLE — Borough and Somerset County authorities are evacuating about 175 residents from the Somerville Senior Citizens Housing complex on Mountain Avenue following a fire there earlier tonight, Mayor Brian Gallagher said.

"We are relocating most with family and friends," Gallagher said about 10:20 p.m.

The fire appears to have been confined to one apartment there, but "significant" water damage from the 9-story building's sprinkler system led to the decision to vacate the complex, he said.

There was no immediate word on whether there had been any injuries.

"Our police and fire and rescue squad are doing a great job," Gallagher said. "It's busy but everybody has good patience. We've obviously got quite a bit of work to do."

The county's Office of Emergency Management has brought two buses to facilitate the move, said Shannon Snook, the office's deputy coordinator.

Gallagher said that community members, including the Somerville Civic League, is helping residents make arrangements.

A spokeswoman from the Red Cross said the agency is partnering with authorities to ensure that everyone finds lodging. The spokeswoman, Diane Concannon, said the Red Cross has so far helped at least 14 people find a place to stay.

"It’s ongoing and very fluid," she said. "We’ll provide assistance as needed."